MicroArray III

Have you ever worked late to put the final touches on a critical project for your company while the network was down for repair? After hours of working on your local system, you click Save. To your horror, you receive an error message that the disk is full and you must delete files to free up space.

You can alleviate many disk space problems if you use a desktop RAID system. These portable systems provide large amounts of storage space for desktop and laptop computers. The MicroArray III, from AIWA RAID Technology, is one desktop RAID system you can choose. The MicroArray III comes with a 5.25", full-drive metal enclosure with three IBM 8.4GB hard disks; a program documentation CD-ROM; a 6', 9-pin null- modem cable; a 2', 9-pin RS-232 internal cable; and a front cover.

Setting Up the Array
I had to reconfigure my system to create a full-height 5.25" space for the MicroArray III. I moved my CD-ROM drive down one bay, which is all my test system required. Other systems might require more reconfiguration.

Because the computer case had metal support tabs, I couldn't insert the MicroArray III completely into the system. To solve this problem, I laid my computer case on its side and placed the MicroArray III on top. This option isn't viable in most circumstances. AIWA should redesign the MicroArray III to alleviate this problem.

Attaching the monitoring cable to the computer was challenging because the MicroArray III is an internal device, but the cable connects to an external COM port. I had to run the cable through an empty slot on the back of the computer to make the connection.

After I rebooted the system and logged on, I inserted the CD-ROM, which automatically activated the software installation wizard. With the wizard's help, I completed each installation step easily. The MicroArray III gives you two installation options: typical or custom. I chose the typical installation, which comes with ArrayView, Adobe Acrobat 3.01, online manuals, and AVI files that illustrate installation processes. The installation requires 96MB of hard disk space, but you need only 42MB of space if you don't install the video manuals. After the installation completed, I rebooted the computer to check that the system recognized the newly attached array.

The MicroArray III ships preconfigured as a three-disk RAID 0 array. You can use the system immediately, but I wanted to set up a new array. I opened ArrayView for Windows, which manages the MicroArray III and provides information about the physical and logical drives. When the ArrayView Search Options dialog box appears, you select the area you want to search for the array (i.e., SPX, Named Pipes, Sockets, or Comm Ports).

My system, which was connected to the local COM port, recognized the MicroArray III within seconds. I opened the Physical and Logical Array windows. In the Physical Array window, I clicked Array, Delete Logical. The system asked me for a password, but I couldn't find a password in the documentation. I called AIWA's technical support group to obtain the default password. I then logged on and deleted the logical drive.

I wanted to create my own RAID 0 logical drive. In the Physical Array window (shown in Screen 1), I clicked Array, Create Logical. I named the array, chose RAID 0, left the default stripe size at 16KB, and added the three hard disks to the Selected window. ArrayView began to configure the drives. After approximately 8 minutes, my 23.6GB RAID 0 logical drive was ready.

The MicroArray III's Logical Array window includes a performance-measuring monitor, which displays read and write information, data transfer speed, I/O per second, and cache and disk usage information. You can view the information in realtime or capture it for later review using graphs or numbers.

A Few Drawbacks
The MicroArray III's design disappointed me because each enclosure can hold only three drives, which is the full-drive requirement for most computers. Scalability is possible using one controller board with an Ultra Wide SCSI host interface that can support as many as 10 MicroArray IIIs. However, the MicroArray III's internal design limits scalability in multiple systems with arrays and multiple array enclosures.

In addition, the MicroArray III has only one non-hot-swappable power supply. If the power supply fails, the array won't work until you power down the system and replace the power supply.

Testing Performance
I used Iometer to test the MicroArray III's I/O speed and response times. Iometer provides disk I/O subsystem measurement and characterization for simulated users (workers) operating a particular system (i.e., single or clustered). Iometer calculated the I/O per second and the average and maximum response times in milliseconds (ms) for the MicroArray III.

(You can download Iometer for free from Intel's Web site--http://developer.intel .com/design/servers/devtools/iometer.)

The MicroArray III's RAID 0 configuration I/O per second was 63.83, about 40 percent slower than Artecon's LynxStak (see "LynxStak 2000," page 100). The average and maximum response times were slower than LynxStak's--15.59ms and 186.7ms, respectively.

A Potential Solution
The MicroArray III is a potential solution for desktop publishing, graphics, CAD, and other computers that require additional fast storage on a desktop system. The ArrayView software lets users configure and monitor arrays quickly, and the hot-swappable hard disks add fault-tolerant storage. However, the non-hot-swappable power supply and three-drive-per-enclosure limitation limit flexibility and prevent you from using the array in mobile environments. The documentation included with the MicroArray III was thorough; the Quick Start Guide was particularly helpful for setting up the system. If you're in the market for additional fast storage for your desktop computer and can overlook the MicroArray III's limitations, consider this RAID hardware product.

End of Article